The present invention relates generally to a method and a system for treating the exhaust gas generated by internal combustion engines, and more particularly to a method and a system for removing particulates and other substances from the exhaust gases generated by internal combustion engines that use hydrocarbons as a fuel.
Various systems, processes, and techniques for treating exhaust gas generated by internal combustion engines to purify or rid the same of atmospheric pollutants are of course well known and may be categorized into several known types of treatment systems or processes.
One such treatment system or process is disclosed as using an aerosol having water particles coated with an oleophilic surfactant is admixed with the internal combustion engine exhaust gas. However, the exhaust gas needs to be initially cooled and is subsequently passed through an expansion turbine so as to cause condensation of water vapor upon the aerosol particles which may then be separated by a suitable separator, such as, a gas centrifuge. It can be appreciated that a system or process such as that disclosed has substantial and diverse equipment through which the internal combustion engine exhaust gas must pass in order to permit the exhaust gas to attain the various stages or states requisite to the treatment thereof.
Another similar or related type of process or system for treating combustion gas to remove pollutants has the products of combustion refrigerated so as to remove the pollutants as a liquid phase. More particularly, the pollutants removed have water formed during the combustion process, as well as pollutants which are substantially soluble in the condensed water. However, with respect to those pollutants which are water insoluble, such as, carbon monoxide, the same must be separately processed. After removal of the water and water soluble pollutants from the exhaust gas by the condensation process, the pollutants are conducted through suitable absorber, such as, a molecular sieve.
Another exhaust emission control system uses condensation techniques, however, such systems are quite complex and involve multiple cooling compression, and expansion stages.
Another type of technology which has been used to extract metals and/or metalloid contaminants from solid and liquid materials and is disclosed in U.S. Pat. No. 5,730,874 issued on Mar. 24, 1998 to Chien M. Wai et. al. The patent includes the extraction of such metals and/or metalloid contaminants from contaminated soils and waste streams, or from metal oxides. The technology discloses that the materials from which the contaminants are to be removed are exposed to a fluid solvent. Supercritical carbon dioxide containing a chelating is used as a preferably agent. The carbon dioxide is noted as having a triple point at approximately five atmospheres (5 atm) of pressure and a temperature of 216xc2x0 K or xe2x88x9257xc2x0 C., and the carbon dioxide is permitted to interact with the metals or metalloid contaminants whereupon the metal chelates are subsequently removed and the carbon dioxide is recycled for reuse.
It does not appear that the foregoing contaminant removal or extraction process has heretofore been applied to the removal of particulates and other substances from the exhaust gases generated by internal combustion engines that employ hydrocarbon fuels, and therefore, it is submitted that a need exists in the art for the application of a process or technology similar to such.
In one aspect of the invention a system for treating and cleaning the exhaust gas of an internal combustion engine from atmospheric pollutants is disclosed. The internal combustion engine uses hydrocarbons as fuel and the system has an emission exchanger, an apparatus which conducts exhaust gas from the internal combustion engine into the emission exchanger, and an apparatus which conducts carbon dioxide (CO2) into the emission exchanger such that the carbon dioxide (CO2) interacts with the internal combustion engine exhaust gas such that atmospheric pollutants are removed from the internal combustion engine exhaust gas by a stream of carbon dioxide (CO2) gas. The cleaned exhaust gas is discharged into the atmosphere.
In another aspect of the invention a method for treating and cleaning exhaust gas of an internal combustion engine from atmospheric pollutants is disclosed. The internal combustion engine uses hydrocarbons as fuel. The method has the steps of: providing an emission exchanger; conducting exhaust gas from the internal combustion engine into the emission exchanger; conducting carbon dioxide (CO2) into the emission exchanger such that the carbon dioxide (CO2) interacts with the internal combustion engine exhaust gas such that atmospheric pollutants are removed from the internal combustion engine exhaust gas by a stream of carbon dioxide (CO2) gas; and discharging the cleaned exhaust gas into an atmosphere.